A NEW METHOD FOR SIMULTANEOUS DETERMINATION OF COBALT AND PALLADIUM

In this paper a new method for the simultaneous determination of cobalt and palladium has been developed with 5-[(5-chloro-2-pyridyl)azo]-2, 4-diaminotoluene (5-Cl-PADAT). When the method is used to determine cobalt only the interference by palladium is eliminated by subtraction. Under the experimental conditions cobalt and palladium form CoR_2 and PdR purple complexes with the reagent respectively. The mole absorptivities of the complexes are e_(Co)=1.20×10~5 and e_(Pd)=6.90×10~4, with the maximum absorption at 570nm. Beer's law is obeyed with the concentration ranges of cobalt of 0～10μg/25mL and palladium of 0～25μg/25mL. The analytical method established has shown desirable senaitivity and selectivity and proved to be successful for the simultaneous determination of trace cobalt and palladium in ore and steel samples.